This is normal and expected. I have a few 20x30" prints from 5D1 and 5D2. They are very close and I don't think most could tell difference. I have read several well known photographers who own both 5D2/5D3 and D800 and they said they could not tell difference either at this size or even at bigger size such as 30x40" prints. Printing on paper like applying a big NR that effectively smear some details.